Semi-analytical method versus the FEM for analysis of the local post-buckling of thin-walled composite structures

The investigations are concerned with a comparison of the semi-analytical method (SAM) and the finite element method (FEM) applied to the local post-buckling analysis of thin-walled composite structures with closed cross-sections, in the second order approximation based on the linear analysis. A ‘lower bound’ approach by Koiter and Pignataro [6] improved in [9], enables us to determine the overall flexural stiffness of an isotropic beam–column after its local buckling. The presented paper verifies the semi-analytical method and the FEM for thin-walled composite structures. The theoretical basis of the present approach is discussed and some typical examples are considered.